Flatland is an 1884 novella by Edwin Abbott about a world of two-dimensional shapes that is one day invaded by a sphere from the third dimension. The narrator, a humble square, explains the society of shapes and their strict caste system. After a sphere passes through Flatland, the square is eventually shown the third dimension. However, the belief in the third dimension is outlawed and when the square returns and preaches its existence, he is imprisoned. The novella explores concepts of geometry and dimensionality, as well as satirizes Victorian society.